blown guage fuse?

Question

i have a 1989 chevy suburban and it keeps blowing my guage fuse
and it will drain down my battery after a few days.
my altenator is good i had it checked.you know that lil trick when you pull your neg battery cable off it will keep runing.when that guage fuse blows and i pull off the neg cable it will die.i will replace the fuse and it keeps blowing them.but after a couple of days put a fuse in it and every thing will be just fine for a couple of weeks or longer and it will do the same thing over agin.i have been told i have a short some where but why does it die when i pull off that neg battery cable

Answer 1

The car dies because alternators (your cars power supply) require a field current to produce power. When you disconnected your battery (the other source of power) the engine could not produce a spark or run the computer and fuel system.
Disconnecting either battery terminal effectively removes the battery from the system. Its always safest to remove the negative terminal first.
You have a serious short in your gauge wiring. I would check the fuel pump wiring. The fuel gauge sender is in your fuel tank with the electric fuel pump.
One of my chevy pickups had the bed removed for work. When they replaced the bed they pinched the wire from the tank and shorted it to the frame. It only shorted out when I put something heavy in the bed.

Answer 2

GM alternators are self exciting and do not require an outside source of electricity to operate. Without the battery, your engine will run off the current charge from the alternator. With the fuse blown, the alternator does not work and when the battery is disconnected, there is no electricity to run.